The present invention relates to industrial processes. More specifically, the invention relates to pressure transmitters used in such processes.
In process pressure instruments, headers are used to pressure-isolate process pressure from electronic circuits while providing for electrical feedthrough connections between electronics which are at atmospheric pressure and a pressurized sensor. The term “header” as used in this application refers to a base that supports hermetically sealed, electrically insulated leads. Deeply penetrating metal welds are often used to seal header joints. The deep penetration of the weld helps ensure a hermetic seal at the weld. The weld also provides sufficient mechanical strength to prevent cracking at the weld.
A large amount of heat is generated in making deeply penetrating welds. Such heat can damage the electrical feedthrough connections. To avoid heat damage to the electrical feedthrough connections, headers typically have large diameters so there is sufficient spacing between the welds and the feedthroughs to provide for adequate heat dissipation.
As pressure sensing devices are increasingly miniaturized, there is a desire to miniaturize the headers. Heat damage, however, has prevented adequate advances in header miniaturization.